1) The document discusses the concept of "planetary boundaries" which aims to define a "safe operating space for humanity" by establishing quantitative boundaries for nine critical Earth system processes. 2) It proposes specific boundary levels for seven of these processes: climate change, ocean acidification, ozone depletion, biogeochemical flows of nitrogen and phosphorus, land use change, freshwater use, and biodiversity loss. 3) The boundaries are meant to avoid crossing critical global thresholds beyond which Earth system processes could be irreversibly altered at the planetary scale, significantly reducing the resilience of the biosphere.

1. Exploring the
Safe
Operating
Space for
Humanity
Prof. Johan Rockström
Stockholm Resilience Centre
Stockholm Environment Institute
Sustainability: prepare for impact
Utrecht University
3rd December 2009
Planetary Boundaries

2. A biosphere shaped by humanity

3. Human growth
20/80 dilemma
Ecosystems
60 % loss dilemma
Climate
550/450/350
dilemma
Surprise
99/1 dilemma
”The Quadruple
Squeeze”

4. Humanity’s period of grace – the last 10000 years

5. Kaufman, Darrell S., et al. 2009. Recent
Warming Reverses Long-Term Arctic
Cooling. Science, September 4, 2009
Steffen, W., et al. 2004
Humanity in the
Anthropocene

6. 5
4
3
2
1
0

7. Critical transitions or regime shifts

8. 1
2
• overfishing, coastal
eutrophication
• phosphorous accum-
ulation in soil and mud
• fire prevention
3
state shift
• disease,
hurricane
• flooding, warming,
overexploitation
of predators
• good rains, continu-
ous heavy grazing
coral dominance
clear water
grassland
4
algal dominance
turbid water
shrub-bushland
Valuable Ecosystem Services Loss of ecosystem services
(Desirable) (Undesirable)

9. The risk of Catastrophic Tipping Points

10. The Resilience of the Earth System

11. Our precarious predicament
”We have our foot on the accelerator
driving towards the Abyss...”
Ban Ki-moon Secretary General of the UN
Sept 2009

12. Planetary
Boundaries:
Exploring the safe
operating space for
humanity in the
Anthropocene
(Nature, 461 : 472 –
475, Sept 24 - 2009)

13. 1. Earth System and sustainability science
(Understanding Earth System processes; ICSU,
IGBP, ESSP, IPCC, MEA, evolution of
sustainability science…)
2. Scale of human action in relation to the
capacity of the planet to sustain it
(Kenneth Boulding Spaceship Earth, Herman
Daly, Club of Rome, Ecological Economics
reserach agenda, Ecological Footprint...)
3. Shocks and Abrupt change in Social-
Ecological systems from local to global
scales
(Resilience, GAIA, tipping elements, guardrails...)
Planetary
Boundaries
concept
PB concept rests on three branches
of Scientific inquiry

14. From:
”Limits to growth”
”Carrying capacity”
”Guardrails”
”Tipping Elements”
To:
”Planetary Boundaries”

15. Two different types of
planetary boundary processes
2. No known global threshold effect1. Critical continental to global threshold

16. Climate
Change
Ocean
acidification
Ozone
depletion
Global
Freshwater
Use
Rate of
Biodiversity
Loss
Biogeochemical
loading: Global
N & P Cycles
Atmospheric
Aerosol
Loading
Land
System
Change
Chemical
Pollution
Planetary
Boundaries

17. Boundary
character
Scale of process
Processes
with global scale
thresholds
Slow processes
without known
global scale
thresholds
Climate Change
Ocean Acidification
Systemic
processes at
planetary scale
Stratospheric Ozone
Global P and N cycles
Atmospheric Aerosol Loading
Freshwater Use
Land Use Change
Biodiversity Loss
Aggregated
processes from
local/regional scale
Chemical Pollution

18. Climate Change
< 350 ppm CO2 < 1W m2
(350 – 500 ppm CO2 ;
1-1.5 W m2)
Ocean acidification
Aragonite saturation
ratio > 80 % above pre-
industrial levels
(> 80% - > 70 %)
Ozone depletion
< 5 % of Pre-Industrial 290 DU
(5 - 10%)
Global Freshwater Use
<4000 km3/yr
(4000 – 6000 km3/yr)
Rate of
Biodiversity Loss
< 10 E/MSY
(< 10 - < 1000
E/MSY)
Biogeochemical
loading: Global
N & P Cycles
Limit industrial
fixation of N2 to 35
Tg N yr-1(25 % of
natural fixation)
(25%-35%)
P < 10× natural
weathering inflow to
Oceans
(10× – 100×)
Atmospheric
Aerosol Loading
To be determined
Land System
Change
≤15 % of land
under crops
(15-20%)
Chemical Pollution
Plastics, Endocrine Desruptors,
Nuclear Waste Emitted globally
To be determined
Planetary
Boundaries

19. Climate Change
what is required to avoid the crossing of critical
thresholds that separate qualitatively different climate
system states
• We suggest boundary values
of 350 ppm CO2 and 1 W m-2
above pre-industrial level

20. Already Committed Global Warming

21. 21
Uncertain uncertainty
ref: Baer and Mastrandrea (2006)
3 ºC 6 ºC

22. 0
2
4
6
8
10
12
14
16
1970 1980 1990 2000 2004
CO2 from fossil fuels and other sources
CO2 from land use change
CH4 from agriculture, waste and energy
N2O from agriculture and others
F gases
Terrestrial and
Marine Carbon
sinks
Adapted from Canadell et al., 2007
0
1
2
3
4
5
6
7
8
9
10
GtCarbon/yr
ocean
land

23. Ocean acidification
Challenge to marine biodiversity and ability of oceans to
function as sink of CO2
• Southern Ocean and Arctic
ocean projected to become
corrosive to aragonite by
2030-2060
Turley et al 2006

24. Ocean acidification
Setting the boundary:
• Globally surface aragonite saturation
state is declining (Ωarag = 3.44 to a
current value of 2.9)
• 2×CO2 Ωarag = 2.29
• Proposed boundary > 80 % pre-
industrial Ωarag = 2.75

25. From R. Buddemeier, based on Kleypas et al. 1999

26. Rate of Biodiversity Loss
Avoid large scale irreversible loss of functional
diversity and ecological resilience
• The current and projected rate of biodiversity loss
constitutes the sixth major extinction event in the
history of life on Earth – the first to be driven by
human activities on the planet
• Biodiversity plays a key role for functional diversity
and thereby ecosystem resilience
• Humans have increased the rate of species
extinction by 100-1,000 times the background rates
that were typical over Earth’s history
• Average global extinction rate projected to increase
another 10-fold, to 1,000-10,000 E/MSY during the
current century

27. Biodiversity Loss
Setting the boundary:
• Suggesting a safe planetary boundary
(here placed at 10 E/MSY)
• within an order of magnitude of the
natural background rate

28. Nitrogen
flow
Agriculturalland use
Ocean
acidity
Freshwater
consumption
Phosphorus
flow
Climate
Change
Atmospheric
aerosolload
Chemical
pollution
Ozonedepletion
Biodiversity
loss
?
?
50-60
70-80
Latest
data
90-00
Pre-
Ind.
?
?
?
?

29. Conclusions
• In the Anthropocene Humanity is, for the first time,
influencing hard-wired processes at the Earth System
scale
• We define the Holocene as the desired stable state
providing necessary environmental pre-conditions for
human development
• We need a new approach to global sustainability and
development that builds on conceptual and knowledge
advancements such as the ”limits to growth” work,
tipping elements, guardrails, carrying capacities.
Scientific insights from research on resilience and complex systems, and
Earth System Science, on the risks of human induced tipping points in a
multitude of Earth system processes and sub-systems
• We propose that a Planetary Boundary framework may
provide one step towards this necessary redefinition

30. • The Planetary Boundaries analysis presented in Nature is
a “proof-of-concept” analysis, with many of the
proposed boundaries being first best guesses. Many
uncertainties remain, and will continue to remain.
• What we suggest is a challenge to the Earth System
Science community to advance further research on Earth
system interactions and non-linear dynamics
• Large Knowledge gaps remain
– Understanding of threshold dynamics
– Boundary interactions and feedbacks
– Spatial variability and patchiness may require global
and regional boundaries
– Allowed overshoot time unclear

31. • No doubt, a Planetary Boundaries approach to sustainable
development would have profound implications for
governance and policy across scales. Large scientific
challenges to address the human dimensions and governance implications of
development within Planetary Boundaries
• Despite uncertainties on allowed overshoot before large
discontinuities, we have enough evidence to act now.
Time is running out on several of the Planetary Boundaries, and the
momentum of driving forces tremendous. This is a first attempt to define the
safe space for human development, which may prove critical in turbulent times
ahead.

33. Land System Change
Avoid unsustainable land system change
predominantly from intensive agricultural use
• Threat to biodiversity and undermining of
regulatory capacity of ecosystems
• Setting the boundary: No more than 15 %
of the global ice-free land surface should
be converted to cropland (12% today)

34. Global Freshwater Use
Avoid water induced environmental change at regional
scale
• Humans now alter global runoff
flows, through withdrawals of blue
water, and changes in green
water flows, affecting water
partitioning and moisture
feedback
• Physical water scarcity when
withdrawals exceed 5000 – 6000
km3 yr-1
• Final availability of runoff
determined by consumptive use
of green and blue water flows
• Consumptive use of blue water an
aggregate control variable with
boundary set at < 4000 km3 yr-1

35. Peter Snyder et al. 2004
Planetary Inter-connections

37. Ozone depletion
Avoiding the risk of large impacts for humans and ecosystem
from thinning of extra-polar ozone layer
• Antarctic ozone depletion a
classic example of an
unexpected crossing of a
threshold
• Our framing on extra-polar
ozone layer depletion
• Identifying a threshold
remains uncertain
• a less than 5% decrease in
column ozone levels for any
particular latitude

38. Chemical Pollution
Steer away from irreversible impacts on living
organisms
• Global, ubiquitous impact on the physiological
development and demography of humans and
other organisms with ultimate impacts on
ecosystem functioning and structure
• By acting as a slow variable that affects other
planetary boundaries (e.g., rate of biodiversity
loss)
• 2 complementary approaches: amounts of
persistent pollutants with global distribution
(e.g., mercury); Effects of chemical pollution on
living organisms
• Difficult to find an appropriate aggregate
control variable. Close interactions with
Aerosol loading; may require sub-boundaries
based on sub-impacts/categories of chemicals

39. Peter Snyder et al. 2004
Planetary Inter-connections

40. Atmospheric Aerosol Loading
Avoid major influence on climate system and human
health at regional to global scales
• Human activities have doubled
the global concentration of most
aerosols since the pre-industrial
era
• Influence on the Earth’s radiative
balance
• May have substantial implications
on hydrological cycle and, e.g.,
Asian monsoon circulation
• Fine particle (PM2.5) air pollution
• Processes and mechanisms
behind these correlations remain
to be fully explained